The first ACP was implanted by Dr. Kevin Walsh in December 2008. Since then, the number of procedures using this device has rapidly grown worldwide. Currently, several registries support the efficacy and safety of the device at both short- and long-term follow-up [6–16]. However, in contrast with the Watchman device [17], there are no randomized studies comparing the use of ACP and oral anticoagulation (OAC) in patients with NVAF. Park et al. [6] published the first ACP registry in 2011 reporting the results of 143 patients who underwent LAA occlusion in different centers across Europe. Although this first registry showed the very initial experience of several operators with the device, the percentage of procedural success reached 96 % and the rate of complications was relatively low with no intra-procedural deaths, cardiac tamponade in 3.5 %, device embolization in 1.4 %, and procedural stroke in 2.1 %. In 2011, Lam et al. [7] also reported the initial Asia-Pacific experience. Similar to the European registry, the procedural success rate reached 95 % and none of the patients presented any intra-procedural complication. Even though these two initial registries showed a high success rate and relatively low number of complications, the procedural outcomes have kept improving over the last few years with the increased experience of operators. As shown in Table 13.1, procedural success ranges between 95 and 100 % according to different series. In addition, the number of complications seems to be decreasing in most of the series as depicted by the reduction of the percentage of cardiac tamponade (0–2 %), device embolization (<1 %), and procedural stroke (0 %). This finding was also observed in the CAP registry [18], a non-randomized continued access program of the Watchman™ system in 460 patients following PROTECT AF [17]. Indeed, the CAP registry revealed a significant improvement of outcomes with the increasing experience of operators, showing a higher successful implantation rate (from 89 to 95 %), shorter procedural times, lower rates of pericardial effusions requiring drainage (from 4.4 to 2.2 %), and lower procedural-related strokes (from 0.5 to 0 %) [18]. Tzikas et al. [19] have recently published the largest registry (1047 patients) on LAA occlusion with the ACP. This large registry is probably the one that reflects better the current overall status of LAA occlusion with the ACP after collecting the initial and subsequent experience of 22 European and Canadian centers. As shown in Table 13.1, procedural success reached 97.3 % and the overall incidence of procedural complications was reduced as compared to the initial registries: procedural stroke (0.9 %), device embolization (0.7 %), cardiac tamponade (1.2 %), and peri-procedural death (0.8 %). Another relevant finding of the study were the indications for LAA occlusion, which reflected the current international practice: previous major bleeding as main indication (47 %), followed by high risk for bleeding (35 %), coronary stenting mandating dual-antiplatelet therapy (DAPT) plus anticoagulation (22 %), and stroke despite warfarin treatment (16 %). This registry also showed the average profile of a patient undergoing LAA occlusion: mean age of 75 ± 8 years with 55 % >75 years old, mean CHADS₂ score of 2.8 ± 1.3, mean CHA₂DS₂-VASc score of 4.5 ± 1.6, and mean HAS-BLED score of 3.1 ± 1.2.